1. Field of the Invention
The present invention relates to a stage driving apparatus for a stage and a probe method and, more particularly, to a stage driving apparatus for a stage and a probe method which can test an object to be tested at high speed.
2. Description of the Related Art
In a semiconductor device manufacturing process, the electrical characteristics of a device formed on a wafer are tested. For example, a prober having a stage driving apparatus for a stage as shown in FIG. 7 is used for this testing. A stage 1 whereon a wafer W is placed and which incorporates an elevating mechanism, an X stage 2 which supports the stage 1 and can move in an X direction, and a Y stage 3 which supports the X stage 2 and can move in a Y direction are arranged in the prober chamber of the prober. When the electrical characteristics of the wafer W are to be tested, the X stage 2 and Y stage 3 are moved in the X and Y directions, respectively. Thus, the stage 1 is moved in the X and Y directions, and the stage is rotated in a θ direction by a rotary mechanism 1a, to align the wafer and a probe card with each other. After that, the stage 1 is vertically moved in a Z direction by the elevating mechanism, to test the electrical characteristics of the wafer W with the probes of a probing card (not shown) in contact with the wafer W.
When a ball screw 2a rotates clockwise and counterclockwise, the X stage 2 reciprocates in the X direction along a pair of guide rails 2b arranged on the Y stage 3. When a ball screw 3a rotates clockwise and counterclockwise, the Y stage 3 reciprocates in the Y direction along a pair of guide rails 3b arranged on a base 4. Reference numeral 3c denotes a motor; 3d, a rotation amount detector. The elevating mechanism of the stage 1 can include, e.g., a ball screw, motor, and elevation guide. When the ball screw is rotated clockwise and counterclockwise by the motor, the stage 1 vertically moves along the elevation guide.
The prober has an alignment mechanism 5 to align the probes of the probing card and the electrode pads of the wafer W with each other. The alignment mechanism 5 includes an upper camera 5b (to imaged sense the wafer W) attached to an alignment moving mechanism 5c, and a lower camera 5a (to imaged sense the probes) provided to the stage 1. The alignment moving mechanism 5c moves from the deepest portion in the prober chamber to the center (in the direction of an arrow Y) along a pair of guide rails (not shown).
The degree of integration of devices is increasing year by year. The number of devices to be tested at once (simultaneous measurement number) increases. The contact load applied by the probes to the wafer W increases greatly. Accordingly, the rigidity of the stage 1 must be increased, so that the weight of the stage 1 increases. In order to improve the throughput of testing, the X and Y stages 2 and 3 and the elevating mechanism must operate at higher speeds. As the diameter or the like of the wafer W increases, the apparatus increases in size and weight.
In the conventional prober, the stage 1 is arranged on the X and Y stages 2 and 3. Thus, the contact load increases, and the rigidity and weight of the stage 1 increase. It has become difficult to operate at higher speeds the elevating mechanism of the stage 1 and the X and Y stages 2 and 3 on which the heavy stage 1 is placed. Accordingly, to increase the speed of testing has become difficult. Due to the rigidity of the ball screws of the elevating mechanism of the stage 1, the limit of the motor torque, and the like, to increase the speed for vertically moving the stage 1 is also limited.